linux-kernel - [PATCH v5 21/24] KVM: arm64: Inject recorded guest interrupts

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Message-ID: <20251209205121.1871534-22-coltonlewis@google.com>
Date: Tue,  9 Dec 2025 20:51:18 +0000
From: Colton Lewis <coltonlewis@...gle.com>
To: kvm@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>, Jonathan Corbet <corbet@....net>, 
	Russell King <linux@...linux.org.uk>, Catalin Marinas <catalin.marinas@....com>, 
	Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	Mingwei Zhang <mizhang@...gle.com>, Joey Gouly <joey.gouly@....com>, 
	Suzuki K Poulose <suzuki.poulose@....com>, Zenghui Yu <yuzenghui@...wei.com>, 
	Mark Rutland <mark.rutland@....com>, Shuah Khan <shuah@...nel.org>, 
	Ganapatrao Kulkarni <gankulkarni@...amperecomputing.com>, linux-doc@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, linux-perf-users@...r.kernel.org, 
	linux-kselftest@...r.kernel.org, Colton Lewis <coltonlewis@...gle.com>
Subject: [PATCH v5 21/24] KVM: arm64: Inject recorded guest interrupts

When we re-enter the VM after handling a PMU interrupt, calculate
whether it was any of the guest counters that overflowed and inject an
interrupt into the guest if so.

Signed-off-by: Colton Lewis <coltonlewis@...gle.com>
---
 arch/arm64/include/asm/kvm_pmu.h |  2 ++
 arch/arm64/kvm/pmu-direct.c      | 20 ++++++++++++++++++++
 arch/arm64/kvm/pmu-emul.c        |  4 ++--
 arch/arm64/kvm/pmu.c             |  6 +++++-
 4 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pmu.h b/arch/arm64/include/asm/kvm_pmu.h
index e4cbab0fd09cf..47e6f2a14e381 100644
--- a/arch/arm64/include/asm/kvm_pmu.h
+++ b/arch/arm64/include/asm/kvm_pmu.h
@@ -92,6 +92,8 @@ bool pmu_counter_idx_valid(struct kvm_vcpu *vcpu, u64 idx);
 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_resync_el0(void);
+bool kvm_pmu_emul_overflow_status(struct kvm_vcpu *vcpu);
+bool kvm_pmu_part_overflow_status(struct kvm_vcpu *vcpu);
 
 #define kvm_vcpu_has_pmu(vcpu)					\
 	(vcpu_has_feature(vcpu, KVM_ARM_VCPU_PMU_V3))
diff --git a/arch/arm64/kvm/pmu-direct.c b/arch/arm64/kvm/pmu-direct.c
index 76d8ed24c8646..2ee99d6d2b6c1 100644
--- a/arch/arm64/kvm/pmu-direct.c
+++ b/arch/arm64/kvm/pmu-direct.c
@@ -413,3 +413,23 @@ void kvm_pmu_handle_guest_irq(u64 govf)
 
 	__vcpu_rmw_sys_reg(vcpu, PMOVSSET_EL0, |=, govf);
 }
+
+/**
+ * kvm_pmu_part_overflow_status() - Determine if any guest counters have overflowed
+ * @vcpu: Ponter to struct kvm_vcpu
+ *
+ * Determine if any guest counters have overflowed and therefore an
+ * IRQ needs to be injected into the guest.
+ *
+ * Return: True if there was an overflow, false otherwise
+ */
+bool kvm_pmu_part_overflow_status(struct kvm_vcpu *vcpu)
+{
+	struct arm_pmu *pmu = vcpu->kvm->arch.arm_pmu;
+	u64 mask = kvm_pmu_guest_counter_mask(pmu);
+	u64 pmovs = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
+	u64 pmint = read_pmintenset();
+	u64 pmcr = read_pmcr();
+
+	return (pmcr & ARMV8_PMU_PMCR_E) && (mask & pmovs & pmint);
+}
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index bcaa9f7a8ca28..6f41fc3e3f74b 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -268,7 +268,7 @@ void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, u64 val)
  * counter where the values of the global enable control, PMOVSSET_EL0[n], and
  * PMINTENSET_EL1[n] are all 1.
  */
-bool kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
+bool kvm_pmu_emul_overflow_status(struct kvm_vcpu *vcpu)
 {
 	u64 reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
 
@@ -405,7 +405,7 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event,
 		kvm_pmu_counter_increment(vcpu, BIT(idx + 1),
 					  ARMV8_PMUV3_PERFCTR_CHAIN);
 
-	if (kvm_pmu_overflow_status(vcpu)) {
+	if (kvm_pmu_emul_overflow_status(vcpu)) {
 		kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 
 		if (!in_nmi())
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index c9862e55a4049..e1332a158dfc8 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -407,7 +407,11 @@ static void kvm_pmu_update_state(struct kvm_vcpu *vcpu)
 	struct kvm_pmu *pmu = &vcpu->arch.pmu;
 	bool overflow;
 
-	overflow = kvm_pmu_overflow_status(vcpu);
+	if (kvm_vcpu_pmu_is_partitioned(vcpu))
+		overflow = kvm_pmu_part_overflow_status(vcpu);
+	else
+		overflow = kvm_pmu_emul_overflow_status(vcpu);
+
 	if (pmu->irq_level == overflow)
 		return;
 
-- 
2.52.0.239.gd5f0c6e74e-goog